EP53A8LQA Datasheet, PDF (12/21 Pages) Altera Corporation – Integrated Inductor

Functional Description
Functional Overview
The EP53A8xQA requires only 2 small MLCC
capacitors and an 0201MLC resistor for a
complete DC-DC converter solution. The
device integrates MOSFET switches, PWM
controller, Gate-drive, compensation, and
inductor into a tiny 3mm x 3mm x 1.1mm QFN
package. Advanced package design, along
with the high level of integration, provides very
low output ripple and noise. The EP53A8xQA
uses voltage mode control for high noise
immunity and load matching to advanced
≤90nm loads. A 3-pin VID allows the user to
choose from one of 8 output voltage settings.
The EP53A8xQA comes with two VID output
voltage ranges. The EP53A8HQA provides
V_OUT settings from 1.8V to 3.3V, the
EP53A8LQA provides VID settings from 0.8V
to 1.5V, and also has an external resistor
divider option to program output setting over
the 0.6V to V_IN-0.5V range. The EP53A8xQA
provides the industry’s highest power density
of any 1A DCDC converter solution.
The key enabler of this revolutionary
integration is Altera’s proprietary power
MOSFET technology. The advanced MOSFET
switches are implemented in deep-submicron
CMOS to supply very low switching loss at high
switching frequencies and to allow a high level
of integration. The semiconductor process
allows seamless integration of all switching,
control, and compensation circuitry.
The proprietary magnetics design provides
high-density/high-value magnetics in a very
small footprint. Altera Enpirion magnetics are
carefully matched to the control and
compensation circuitry yielding an optimal
solution with assured performance over the
entire operating range.
Protection features include under-voltage lock-
out (UVLO), over-current protection (OCP),
short circuit protection, and thermal overload
protection.
Integrated Inductor: Low-Noise Low-EMI
The EP53A8xQA utilizes a proprietary low loss
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EP53A8LQA/EP53A8HQA
integrated inductor. The integration of the
inductor greatly simplifies the power supply
design process. The inherent shielding and
compact construction of the integrated inductor
reduces the conducted and radiated noise that
can couple into the traces of the printed circuit
board. Further, the package layout is
optimized to reduce the electrical path length
for the high di/dT input AC ripple currents that
are a major source of radiated emissions from
DC-DC converters. The integrated inductor
provides the optimal solution to the complexity,
output ripple, and noise that plague low power
DCDC converter design.
Voltage Mode Control, High Bandwidth
The EP53A8xQA utilizes an integrated type III
compensation network. Voltage mode control
is inherently impedance matched to the sub
90nm process technology that is used in
today’s advanced ICs. Voltage mode control
also provides a high degree of noise immunity
at light load currents so that low ripple and high
accuracy are maintained over the entire load
range. The very high switching frequency
allows for a very wide control loop bandwidth
and hence excellent transient performance.
Soft Start
Internal soft start circuits limit in-rush current
when the device starts up from a power down
condition or when the “ENABLE” pin is
asserted “high”. Digital control circuitry limits
the V_OUT ramp rate to levels that are safe for
the Power MOSFETS and the integrated
inductor.
The EP53A8HQA has a soft-start slew rate that
is twice that of the EP53A8LQA.
When the EP53A8LQA is configured in
external resistor divider mode, the device has a
fixed VOUT ramp time. Therefore, the ramp
rate will vary with the output voltage setting.
Output voltage ramp time is given in the
Electrical Characteristics Table.
Excess bulk capacitance on the output of the
device can cause an over-current condition at
startup. Assuming no-load at startup, the
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